airlines flight 370, officials from malaysia, australia and france are vowing to press ahead to find the plane. >> i'm quietly confident that we are on the right track. >> reporter: while the aerial hunt was called off earlier this week, authorities plan to expand the under water hunt for the aircraft. australian officials, though, express doubts today that an unmanned u.s. navy submersible that's been scanning a remote part of the indian ocean would find any wreckage. >> i must say, the chances of finding it i think the probability is lower than it was when we started the search. >> reporter: on thursday, malaysian officials released a preliminary report. the five-page document confirmed radar tracked the plane as it turned west but that air traffic controllers did not realize the boeing 777 was missing until 17 minutes after it disappeared from civilian radar. >> all that will be investigated. >> reporter: families of the 239 missing passengers and crew members remain frustrated at the lack of progress. after weeks of waiting in a hotel, they were advised thursday to return home. s